ok i recently went from a 2.73 ratio ring an pinion to a 3.73 ratio ring and pinion now i need a different spedo gear
i have an 89 rs with a stock 700r4

where can i find out which one i need and where to get it?

 

www.summitracing.com has them. just put in your make/model stuff and look into the drivetrain section. there is a calculator requiring the rear end ratio, tire diameter, and possibly transmission ratios. its just about fool proof to order the wrong ones

 

i could only find 2 spedo drive gears one was 15 tooth an one was 43 tooth
i dont know how to calculate what drive gear i need.

if i have to go to a larger or a smaller gear how will it still work?
either the gear would be too big and wont fit or would be too small and not reach the other gear

 

hmm, they used to carry them. i cant find them on summit now. jegs does carry them, you just have to find the ones for the 700r4. when they are being replaced, the drive and driven gear get replaced to alter the ration and so they mesh. its not just one gear that gets smaller/larger.

the calculations are on this page for example use: http://www.jegs.com/i/TCI/890/880018/10002/-1

p.s. that may be what you are looking for as well, its 82-93 700r4

 

um if i find say an iroc in the junkyard an it has a 3.73 rear end the spedo gears will swap with no probs right?

 

No with the junkyard crap...my god. Some guys waste so much time and energy. You're better off getting the right one, thats in perfectly new condition.....
Plus, GM changed out the speedo cover housing at somepoint (recall that no body did) and its a p.i.t.a to find an original....(so don't break it!)

There are a bunch of sites dedicated to 700R4/4L60 from mild to wild, that will have exactly what you're looking for. I did mine and think all said and done it was under 30..and I didn't have to crawl around the junkyard.

 

Here ya go: http://www.transmissioncenter.net/sp...n_______va.htm

 

That is exactly who I got all my speed stuff from. They were great.

 

are the rear ends tagged with the axle ratio?

 

I accept with information:There are a bunch of sites dedicated to 700R4/4L60 from mild to wild, that will have exactly what you're looking for.